Radio tuning coil



Oct. 18, 1927.

G. c. BRooKs, JR

RADIO TUNING COIL Filed April 11, 1925 5 Sh eets-Sheetl 1 N VEN TOR 6 0076 Claz'anae Brooizmfir W I TNESSE'5.

"H15 A TTORNE Y Oct. 18,1927. 1,646,231

6. c. BROOKS, JR

RADIO TUNING 6011.

Filed April 11. 1925 s Sheets$heet 3 WITNESSES. INVENTOR Z Zea/ye Clare/2C6 Ema/5.46:

Patented Oct. 18,1927.

"UNITED. STATES GEORGE CLARENCE BROOKS, J'B., OF CAMDEN, NEW JERSEY.

RADIO TUNING COIL.

- Application filed April 11, 1925. Serial No. 22,354.

My invention relates to tunin coils especially designed for use with ra 1o recelving apparatus.

The current losses in tunlng coils are largely caused by defective insulation between the coil turns and the losses are mcreased if the insulating material becomes moist. These losses are detrimental to proper reception of broadcast matter. The coils in use are of two classes, covered wire coils, and bare wire coils. The chef ob ection to the covered wire coils is that the insulating covering absorbs moisture. The chief objection to the bare wire 0011s is that the coil turns, being necessarily spaced from each other, make a large and clumsy coil which is undesirable. Another ob ection common to both types of coils is that it is practically impossible to eliminatehowls and other tube noises without sacrificmg regeneration.

The objects of my invention are to provide a neat and compact tuning coil which will be practically free from current losses due to insulating material between 1ts turns; which may be easily controlled to eliminate howls and other tube noises; which Wlll have maximum regeneration at all times; which is sensitive and selective in tuning, and with which broadcast matter may be received with a great volume and clearness of tone.

These objects, and other advantageous ends which will be described hereinafter, I attain in the. following manner, reference bein had to the accompanying drawings in whici Figure 1 is a side elevatlon of a tuning coil made in accordance with my invention illustrating it attached to apanel,

Figure 2 is a diagram of the electrical con-" nections between the tuning coil shown in Figure 1 and radio receiving apparatus,

Figure 3 a central vertical section through the coil shown in Figure 1,

Figure 4 a section on line 4-4 of Figure 3, Figure 5 a section on line 55 of Figure 3, and

' Figure 6 a bottom shown in Figure 1.

Referrin to the drawings, particularly Figure 2, tfie aerial circuit includes an aerial 1, a primary 2 and a ground 3; the grid circuit, a main secondary 4, a supplemental secondary 5, primary 2, and the filament 6 and grid 7 of an audion tube; and the aerial plan view of the coil circuit, a plate 8, an adjustable regeneration coil 9, a fixed regeneration coil 10, recorders 11, batteries 12 and filament 6.

The secondary coils 4 and 5, primary coil 2 and regeneration coils 9 and 10 are mounted on a frame 13 of insulating material. This frame is made up of an inner series of rods 14 and an outer series of rods 15 of insulating material connected and spaced from each other by insulating spacers 16 at one end and 17 at the other end. The spacers are preferably of ring shape and connected to the inner series of rods 14 by fitting the rods in holes 18 in the spacers. The outer series of rods 15 is connected to the spacers by securing the rods in slots 19 in the periphery of the spacers. This facilitates the securing of the outer series of rods 15 to the spacers after a coil has been wound around the inner series of rods 14.

Each of the rods 14 and 15 has grooves 20 therein for receiving and properly spacing the bare wire turns of the coils. The main secondary 4 is wound around the inner series of'rods 14 with its turns within the grooves. Its end is then brou ht out between rods 15 and wound aroun them with the wire turns within their ooves to make up the supplemental secon ary coil 5 and the primary 2. The aerial is connected to a terminal 22, which is connected to one end of the primary 2 at 23. The other end of the primary is connected with a terminal 24 adapted to be connected with the ground 3. The free end of the main secondary is connected with a terminal 25 adapted to be connected with grid 7. The fixed regeneration coil 10 is wound around the outer series of rods 15 with its turns within grooves 20 and has one end connected with a terminal 26 and the other end connected through aterminal 27 to the adjustable regeneration coil 9.

- Terminals 24 and 26 being mounted near each other on spacer 1 7, allow a by-pass condenser. 28, which brid es recorders 11 and batteries 12 shown in F1gure 2, to be directly connected to the terminals, as shown in Figures 4 and 6. This eliminates a separate condenser mounting and shortens the connecting wires of the condenser.

Adjustable regeneration coil 9 is wound to embrace the ends of a bar 29 having grooves 30 in which the turns of the coil are mounted. Bar 29 is suitably secured to a shaft 31, which is slidable and rotatable in a bearing 32 secured to a bracket 33 extending from spacer 16. Bearing 32 is preferably in the form of a. bushing which may extend through a panel 34: and be secured thereto by a nut 36, and thus serve as a means for attaching the tuning coil to a panel.

By connecting the main secondary in series with the supplemental secondary and the primary, greater selectivity is obtained without having the losses inherent in tuning coils inductively coupled. By providing a fixed regeneration coil adjacent the primary so that it overlays one end of the secondary, and another adjustable regeneration coil near the other end of the secondary, howls and other tube noises may be eliminated and maximum regeneration obtained at all tlmes. By mounting shaft 31 slidably and rotatably in the bearing, coil 9 may be shifted and rotated as shown in dot-and-dash lines in Figures 3' and 5 tothe position in which best results are obtained and thus give a wide range of adjustment. By using bare wire and mounting it on a series of grooved spaced insulating rods, as above described, the insulating material between the coil turns is minimized and current losses decreased, and the size of the tuning coil 1s reduced.

In actual use I have found this tuningcoil to be very sensitive for distant reception; to produce a greater volume and clearness of tone than known coils and to be easily controlled to eliminate howls and other tube noises without sacrificing the volume of tone.

While I have described my invention as taking a particular form, it will be understood that the various parts may be changed without departing from the spirit thereof, and hence I do not limit myself to the precise construction set forth, but consider that I am at liberty to make such changes and alterations as fairly come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary, and a primary comprising a portion of the supplemental secondary being spaced from and overlaying the main secondary.

2. In a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary; a primary comprising a portion of the supplemental secondary and overlaying the main secondary, and a regeneration coil adjacent the primary and overlaying the main secondary.

3. In a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary; a primary comprising a portion of the supplemental generation coil and disposed at the other secondary and overlaying the main secondary; a fixed regeneration coil at one end of the main secondary, and an adjustable regeneration coil in series with the fixed regeneration coil and disposed at the other end of the main secondary.

4:. In a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary; a primary comprising a portion of the supplemental secondary and overlaying the main secondary; a fixed regeneration coil overlaying one end of the main secondary, and an adjustable regeneration coil in series with the fixed reend of the main secondary.

5. In a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary: a primary comprising a portion of the supplemental secondary and overlaying the main secondary; a fixed regeneration coil overlaying one end of the main secondary, and an adjustable regeneration coil in series with the fixed regeneration coil and disposed at the other end of the main secondary, the adjustable regeneration coil being normally disposed within the main secondary.

6. In. a tuning coil a main secondary; a supplemental secondary in series with and overlaying the main secondary; a primary comprising a portion of the supplemental secondary and overlaying the main secondary; a fixed regeneration coil adjacent the primary and overlaying the main secondary, and an adjustable regeneration coil in series with the fixed regeneration coil and normally disposed within the main secondary.

7. A tuning coil including two series of insulating coil holding elements disposed one series within the other; spacers secured to the elements for keeping them apart; a main secondary wound on the inner series of coil holding elements; a supplemental secondary in series with the main secondary and wound on the outer seriesof elements, and a primary wound on the outer series of elements and connected in series with the supplemental secondary.

8. A tunin coil including two series of insulating coi holding elements disposed one series within the other; spacers secured to the elements for keeping them apart; a main secondary wound on the inner series ofelements; a supplemental secondary in series with the main secondary and wound on the outer series of elements; a primary wound on the outer series of elements and connected 1n series with the supplemental secondary; a fixed regeneration coil wound on the outer series of elements, and an adjustable regeneration coil in series with the fixed regeneration coil and disposed at the end of the main secondary. a

9. A tuning coil including two series of insulatingcoil holding elementsdisposed one series within the other; spacers secured to theelements for keeping them apart; a

main secondary wound on the inner series of elements; a supplemental secondary in series with the mam secondary and wound on the outer series of elements; a primary wound secondary winding on the inner series of elements; a supplemental secondary'wlndlng on the outer senes of elements and n Series with the main secondary winding; a primary a winding on the outer series of elements and connected in series with the supplemental secondary winding; a fixed regeneration winding on the outer series of elements; a

bracket mounted-on one of the s acers; adustabIemeanS mounted 1n the racket; a regeneration winding mounted on sa1d means and connected in series with the fixed regen-- eration winding, and terminals on the other spacer and electrically connected with the windings.

In testimony whereof Ihave signed my name to this specification.

GEORGE CLARENCE BROOKS, JR. 

